English is an Evolving Language

I am so tired of people using that excuse to justify laziness in their writing. Yes, English is constantly adding new words and losing old ones. However, that's vocabulary. Spelling is pretty much standardized and has been for decades. Grammar and punctuation are set in stone.

Now, if they had said English is a _flexible_ language they would have had a better case. But still not a good one. If you're going to be casual in your writing, admit it. There's nothing wrong with being casual in most circumstances. Just don't try to pretend your mistakes aren't really mistakes.